Nation

MH370 search: Time to go underwater, says JACC chief

PERTH: An Australian vessel leading the hunt for missing Malaysian jet MH370 will deploy a mini-sub, the Bluefin-21, on Monday, according to Joint Agency Coordination Centre head Angus Houston.

"Ocean Shield will cease searching with the towed pinger locator later today (Monday) and deploy the autonomous underwater vehicle Bluefin-21 as soon as possible," said Houston.

Houston said that in the hunt for the plane's black box transmissions, the last signal was logged six days ago. "We haven't had a single detection in six days so I guess it's time to go underwater," he said at a press conference in Perth.

The mini-sub, the Bluefin-21

Houston also said that the deployment would be on a 24-hour cycle and would cover a search area of 40 sq km.

An oil slick had also been spotted in the search area, Houston said, with around two litres of fuel collected for testing.

"I stress the source of the oil is yet to be determined but the oil slick is approximately 5,500m downwind... from the vicinity of the detections picked up by the towed pinger locator on Ocean Shield," he said.

It would be a number of days before the oil could be conclusively tested ashore, but Houston said he did not think it was from a search vessel.

He emphasised that it was 38 days since the Boeing 777 vanished on March 8 and the black box batteries had a shelf life of only 30 days.

The US-made Bluefin-21, a 4.93-metre (16.2 feet) long sonar device will now scour the seabed.

The sonar device, which weighs 750kg, can operate at a depth of up to 4,500m - roughly the depth of the ocean floor where the pings were detected.

MH370 disappeared soon after taking off on March 8 from Kuala Lumpur for Beijing with 227 passengers and 12 crew on board, triggering a multinational search that is now focused on the Indian Ocean.

Search aircraft and vessels have been scouring an area north-west of Perth, after picking up four acoustic signals that they believe are from the plane's black box recorders.

Up to 12 aircraft and 15 ships are involved in Monday's search for the missing plane.